To date, the United States has confirmed a total of 160 human cases of influenza A (H1N1): 4 in Arizona, 24 in California, 2 in Colorado, 1 in Connecticut, 4 in Delaware, 2 in Florida, 3 in Illinois, 3 in Indiana, 2 in Kansas, 1 in Kentucky, 8 in Massachusetts, 2 in Michigan, 1 in Minnesota, 1 in Missouri, 1 in Nebraska, 1 in Nevada, 7 in New Jersey, 50 in New York, 1 in Ohio, 13 in South Carolina, 28 in Texas and 2 in Virginia. Other suspected cases are being investigated. 6 hospitalizations and a death have been registered. The dead case is a child of 22 months old. The age range of the confirmed cases is from 22 months to 81 years (a median of 16 years).

From 17 April to May 1st, Mexico has reported 4,691 suspected cases of influenza with severe pneumonia including 99 deaths. The significant increase in the number of suspected cases is due to the change in the case definition. Previously, a suspected case was one that presented fever, cough, and difficult breathing. Now, it is one that presents fever and at least one of the following symptoms: cough or odynophagia (sore throat upon swallowing). The suspected cases were recorded in all Mexican states. The most affected are: Aguascalientes, Baja California, Distrito Federal, Durango, Estado de México and San Luís Potosí. The majority of these have occurred in previously healthy young adult people. There have been few cases in individuals under 3 or over 59 years old. 1,262 of the suspected cases have required hospitalization.

The number of probable cases of influenza A (H1N1) is 105, while 397 cases have been confirmed, with 16 death cases among them. The considerable variation in the number of confirmed cases as of today is due to the recent laboratory confirmation of samples collected in previous weeks.

In Canada, to date 51 human cases of influenza A (H1N1) have been confirmed (8 in Alberta, , 15 in British Columbia, 1 in New Brunswick, 14 in the province of New Scotland, 1 in Quebec and 12 in Ontario) some of them with recent trip history to Cancun, Mexico. All the cases developed a mild form of influenza like illness. 2 of the cases presented, in addition, gastrointestinal symptoms. All of them are currently recovered and none required hospitalization. Laboratory tests were conducted in Winnipeg, Canada. Indigenous transmission is not discarded since not all the confirmed cases have trip history to Mexico